The Olloclip quick-connect camera lens is a pretty cool tool which drastically enhances the quality and functionality over your standard iPhone camera lens. Specifically designed for the iPhone 4 or 4S, The Olloclip comes with three lens options. A fisheye lens which captures practically a 180 degree field of view, the wide angle lens which doubles the standard field of view, and the macro lens which helps you focus the iPhone within 12-15mm of your subject.
